Formation and properties of volume and relief holographic gratings in photopolymer materials

Subject of study. Formation conditions, diffraction, and selective properties of various types of holographic gratings in photopolymer materials are studied. Aim of study. The diffraction and selective properties of one-dimensional non-slanted and slanted gratings, relief gratings, hybrid structures, and two-dimensional gratings in various photopolymer materials under a wide range of radiation incidence angles in three-dimensional space are investigated, and the conditions for expanding the angular range in which high diffraction properties are achieved is determined. Methodology. Unlike traditional techniques, transmission gratings’ diffraction efficiency and angular selectivity were studied using the incidence of radiation in a wide angular range in different planes with changes in grating orientations. Main results. The conditions for obtaining effective transmission volume gratings in advanced photopolymer materials and their properties are determined. It is shown that, when the radiation is incident in the Bragg plane, the maximum diffraction efficiency is achieved in the angles ranging up to 80° with the full width at half maximum of the angular selectivity contour up to 120°. Maximum diffraction efficiency is achieved in some directions of radiation passage through the grating (oblique transmission) that differ from the traditional Bragg direction. The maximum diffraction efficiency is achieved at large angles of incidence, approximately 70°. The conditions for forming effective hybrid structures combining the properties of a volume and relief grating are determined. It is shown that the range of radiation incidence angles is extended due to the contribution of the relief component of the hybrid structure. The possibility of obtaining effective relief gratings in a previously unexplored serial photopolymer material is shown. The conditions for obtaining effective two-dimensional gratings with the possibility of a smooth change in the intensities in diffracted beams when the element is rotated are determined. Practical significance. Angular range expansion can be achieved by varying the characteristics and orientation of the gratings, eliminating the need for stacked elements. The established properties of holographic gratings can be used to solve problems in solar energy, diffractive optics, and security printing technologies.